Influence of different ratios of Fe and N on the structural, mechanical, electronic properties of FexNy compounds: First-principles study

Abstract

The influences of different ratios of Fe and N on the structure, mechanical and electronic properties of Fe[Formula: see text]N[Formula: see text] compounds were studied by using the first-principles study. Our obtained lattice parameters are in excellent agreement with the experimental data. The calculated density of the Fe[Formula: see text]N1 compounds increases with the Fe content, which is almost consistent with the trend of the experimental results. The elastic constants indicate that the Fe[Formula: see text]N[Formula: see text] compounds are mechanically stable. The values of [Formula: see text]/[Formula: see text] and Poisson’s ratio indicate that the Fe[Formula: see text]N[Formula: see text] compounds exhibit ductile manner. As Fe content increases, [Formula: see text]/[Formula: see text] and Poisson’s ratios decrease monotonically. In particular, Fe4N1 has the highest hardness among all the considered Fe[Formula: see text]N[Formula: see text] compounds. The obtained density of states shows that Fe[Formula: see text]N[Formula: see text] is metallic in nature. The peak of the state density becomes sharper with the increase of N content, indicating that the localization of these alloys is enhanced. Among the Fe[Formula: see text]N[Formula: see text] compounds, Fe1N1 has been found to be the most stable with respect to the band filling theory calculation.